Beds are general goods for sleeping or resting in a comfortable state, and are mainly designed in consideration of a functionality of sleeping and resting, and an aesthetic design as interior furniture. Meanwhile, an ordinary bed in which a flat mattress is installed may cause pain in a back or other parts in a case in which a user uses the bed for a long time period. Particularly, in the case of patients with a physical disability affecting a body part such as an arm or leg or the elderly who stay in bed for a long time period, health of the user is not good due to lack of exercise. This kind of problem also occurs in ordinary persons who are busy and tired so that it is difficult to secure time to exercise.
In consideration of such a problem, a bed in which exercise apparatuses are provided in a conventional bed, a user who is in the bed or under recuperation or treatment can exercise with the exercise apparatuses included in the bed before and after sleeping without departing from the bed has been known. However, in such a conventional bed, since the exercise apparatuses mostly protrude and are exposed at an outside of the bed, in a case in which the bed has to be used for an original purpose of a bed such as sleeping or resting without exercising, there are problems in that the exercise apparatuses may be a cumbersome obstacle and an exterior design may not be good. Accordingly, the bed having the exercise apparatuses does not have a specific problem when applied as a bed of a medical institution or sports center having a main purpose of medical rehabilitation, recuperation, or exercising, but is unsuitable to be applied to a bedroom installed in a house, hotel, or condominium in which the original function of bed such as sleeping or resting or an exterior design is more important.